ZnO-based electrolyte-gated transistor (EGT) applied as multiparametric UV-sensing device

Abstract

Transistors based in solution-processable semiconducting metal oxides stands out for disposable, printed and wearable electronics. Here we report a transparent and printed ZnO-based electrolyte-gated transistor (EGT), using cellulose electrolyte, which exhibited low-voltage operation, below 2 V, threshold voltage of 0.16 V, high on-state current of 0.3 mA, I on /I off ratio of 3.0×10 5 and field-effect mobility of 0.17 cm²/Vs. We have demonstrated that such EGT can be applied as an ultraviolet sensing device, showing multiparametric response with shift in its: threshold voltage (V T ), subthreshold swing (S), transconductance (g m ) and enhancement in the field-effect mobility in saturation regime ( μ s ) when exposed to different UV irradiance levels. This device achieves high I UV /I dark ratio, responsivity and EQE of 1×10 5 , 8.4×10 4 A/W and 2.7×10 6 %, respectively, presenting very stable properties when tested in ambient atmosphere, without encapsulation, and with no visible effects of ageing during the period of observation. The variation in the transistor parameters and the high values of the figures of merit for photodetectors, categorize this EGT as a multiparametric UV sensor with good performance and compatible with printed and transparent electronics. • A transparent ZnO-based electrolyte-gated transistor was successfully fabricated by a simple solution route with low-cost process; • The transistor was applied as an ultraviolet sensor that operates at low-bias; • The threshold voltage, subthreshold swing, transconductance and field-effect mobility shifted under different UV irradiance intensities, evidencing the multiparametric response characteristic of the transistor applied as sensor; • The photodetector presented high responsivity of 8.4×104 A/W and high external quantum efficiency of 2.7×106%.